centos切换源
CentOS 5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo
CentOS 6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
CentOS 7
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
CentOS 8
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-8.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-8.repo
CentOS 8-stream
minorver=8-stream
sudo sed -e "s|mirrorlist=|#mirrorlist=|g" \
-e "s|^#baseurl=http://mirror.centos.org/\$contentdir/\$stream|baseurl=https://mirrors.aliyun.com/centos-vault/$minorver|g" \
-i.bak \
/etc/yum.repos.d/CentOS-*.repo
重新生成缓存：
dnf clean all
dnf makecache
centos7.8升级内核：
yum -y install http://mirror.cloud.idcsmart.com/cloud/kernel/5.4.166/kernel-lt-5.4.166-1.el7.elrepo.x86_64.rpm
grub2-set-default 'CentOS Linux (5.4.166-1.el7.elrepo.x86_64) 7 (Core)'
网卡驱动之类的：
yum --enablerepo=elrepo-kernel install kernel-ml-devel
rpm -qa | grep kernel
查看可用内核
saved_entry=kernel-lt-5.4.166-1.el7.elrepo.x86_64
grub2-set-default kernel-lt-5.4.166-1.el7.elrepo.x86_64
切换启动内核版本
grub2-editenv list
查看修改结果
